Extension tower



/- 1,638,611 Aug- 9 1927' w. M. BALDWIN EXTENSION TOWER Filed Nov. s. 1922 s sheets-sheen 31a/uc '111015 ug- 9 1927- w. M. BALDWIN EXTENS ION TOWER Filed Nov. 5, 1922 3 Sheets-Sheet 2 Aug. 9,1927. 1,638,611-

W. M. BALDWIN EXTENSION TOWER Filed Nov. 5, 1922 3 Sheets-Sheet 3 :JM/vanto@ M139 il w www atten nu* s .Patented Aug. 9, 1927.

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UNITED STATES PATENT OFFICE.

WILLIAMM. BALDWIN, OF TRENTON, NEW JERSEY, ASSIGNOR TO J. R. MGCARDELL & C0., OF TRENTON, NEW JERSEY, A CORPORATION F NEW JERSEY.

EXTENSION TOWER.

Application led November 3, 1922. Serial N o. 598,889.

This invention relates to tower structures of the extensible type intended f or use, primarily, upon vehicles employed in construction or repair work upon elevated structures, such as the trolley wires of electric railways.n

The invention is an improvement upon the device shown in the patent to J. O. Mc- Cardell et al, No. 534,07 5, granted Feb. 12, 1895, which discloses the construction employed before the present invention.

An object of the invention is to aiiord a tower which may be readily raised and lowered and which, when collapsed, has a center of gravity materially closer to the vehicle body structure than towers heretofore used. In other words, itis an ob]ect of the present invention to minimize and eliminate, so far as possible, the toplieaviness present in former devices of a similar character when the tower is lowered.

Another object of the invention is to improve the means for locking the revolving platform supported upon the top tower. section whereby the same may be positively held in any selected position.

Other objects of the invention relateto the meansfor hoisting the tower, to the rigging arrangement and its details, and to other features of the tower which will be hereinafter clearly set forth.

In the accompanying drawings there is shown one embodiment of the invention, and in the drawings Fig. 1 is a side elevational view of a truck showing the tower lowered or collapsed,

Fig. 2 is a side elevational view showing the tower raised,

Fig. 3 is a top plan view,

Fig. 4 is an enlarged detail of the tower taken at a right angle to the view shown in Fig. 1, and

Fig. 5 is a plan view of the windlass operating mechanism.

In the several views indicates conventionally a truck of a suitable type upon which is positioned the tower, which, as shown in Fig. 2, comprises a lower stationary section 11 of substantially square or rectangular construction, an intermediate section 12 and a top section 13. All of the sections are of substantially the same general shape, but of slightly 'different dimensions so that they may be arranged in telescopic relation with the intermediate section 12 fitting within the bottom section 11 and the top section 13 having a sliding lit in the intermediate section. Each section coniprises vertical corner posts 14 connected on their opposite sides by diagonal trusses 15 and by horizontal braces 16 at the. front and rear of the tower, which serve as steps to permit the Workmen to ascend the tower.

By reference to Fig. 4 it will be noted that the top brace 16 is centrally bowed downwardly at the front and rear of the tower in order to accommodate the sections to the hoisting mechanism later to be described.

The top section 13 carries cross members 18 (Fig. 3) which, at their center, support a king bolt 19, serving as a pivot for a platform 20. The platform carries on its under face rollers 21 positioned above a circular rail or track 22 fixedly secured to the top section 13.

In order to lock the platform in position it has secured thereto a plate 23 having an extension 24 provided with an opening 25 positioned beyond the edie of the platform. The track 22 carries a plurality of peripheral lugs 26 provided with openings 27 with which the opening in the plate 24 may be placed in registry. A Wedge or other suitable locking member 28 secured to the platform by a flexible connection 29 is adapted to be inserted through the plate opening and lug openin when the plate is positioned above one of t ie lugs and thereby the platform is held against rotation. To insure safety it will be noted that the-platform is provided with side rails 30 which, as shown in Fig. 1, may be folded downwardly upon the surface of the platform when the tower is collapsed.

The tower is particularly useful in repair work upon overhead electric cables, and for this purpose the platform has therein a covering 31 (Fig. 4), of non-conducting or insulating material, such as rubber, whereby the workmen are safeguarded when the tower is employed in this manner.

For the purpose of raising and lowering the tower a windlass 32 is positioned beneath the bottom stationar section and has bearings in the side members 10 (Fig. 5) of the vehicle chassis. FlexibleI connections, such as ropes 33, are secured to the windlass and extend from opposite sides thereof over sheaves 34 at the base of the bottom section. The connections are carried upwardly over sheaves 35 at the top of the stationary secl tion, then downwardly within the stationary section over the sheaves 36 adjacent the base of the intermediate section. The connections ext-end upwardly within the 1ntermediate tower' section and pass to thc exterior thereof between the horizontal braces 16, then traverse sheaves 37 at the top of the intermediate section, subsequently extendlng downwardly Within the intermediate section to the base of the top section to whlch the are secured, as at 38. Operation of the win lass will result in hoisting of the tower to the position shown in Fig. 2 from that show n in Fig. 1. Preferably, when the tower 1s positioned upon a motor vehicle, means are provided whereby the tower may be hoisted and lowered by either hand or power operated mechanism. For this purpose, at one side of the'vehiele the windlass shaft 39 is extended through a bearing strlp 40 secured to the side of the vehicle frame. The shaft has lixedly mounted thereon a gear 41 meshing with a pinion 42 upon -a shaft 43 which also carries a gear 44 meshing with a pimon 45 upon a shaft 4 6. The shaft 46 has mounted thereon a sprocket wheel 47 traversed by a chain 48 or other suitable drivmg connection which may fbe operated from the vehicle power plant. The end of the shaft 46 is extended outwardly beyond the bearing strip 40 and is squared so as toreceive a hand crank whereby the gearing above described may be operated manually, if desirable to actuate the windlass in this manner.

A, brake drum 49 is also secured to the shaft 46 and is surrounded by a brake band 50 which is operated by means of a lever 51 (Fig. l) pivotally secured at 52 to the bearing strip .40. This brake will be found partieularly useful in lowerlng the tower.

The tower, when constructed as set forth.

with three sections, is found to be a decided improvement upon towers heretofore employed; its weight when the upper sections be readily raised and lowered by a single operator when hand power is employed, although the windlass actuating mechanism is of a character which freely permits use of the vehicle motor power for this purpose.

It will'he understood that although the present invention relates to detailed improvements upon the tower construction previously employed, numerous details ofthe device set forth may be varied without departing from the scope of the invention.

I claim:

- An extensible tower of the class described comprising three telescoping seetions adapted to be positioned in nested relation when the tower is lowered, sheaves mounted at the top of the outer section on opposite'sidcs thereof, and having their axes arranged below the top of the section Whereby the sheave does not extend above the top thereof, sheaves at the base of the intermei diate section on opposite sides thereof, and a pair of sheaves at the top of the intermediate section with their axes arranged substantially below the top of said section, the outer section having cross bars at its top bowed downwardly adjacent said top sheaves .substantially below the peripheries of the sheaves, a windlass associated with the tower and fiexible hoisting means extending from opposite sides of said windlass over -said sheaves and secured to the bottom of the innermost section, said innermost section having a revoluble platform thereon.

In testimony whereof I have hereunto set my hand.

WILLIAM M. BALDWIN. 

